复方硫酸亚铁缓释片中硫酸亚铁的释放度的测定

目的建立复方硫酸亚铁缓释片中硫酸亚铁的释放度测定方法。方法以0.1 mo.lL-1盐酸溶液1 000 m l为溶出介质,转速为100 r.m in-1,溶出量采用比色法测定。结果本品中硫酸亚铁的释放符合H iguch i释药方程,并与国外上市的同规格产品Ferrograde Folic一致。结论符合中国药典2000版附录X I X D关于缓释制剂的相关规定。     

辛伐他汀胃漂浮型缓释片的制备及体外释放研究

目的筛选辛伐他汀胃漂浮型缓释片最优处方,并考察其漂浮性能及体外释药情况。方法采用正交法筛选出辛伐他汀胃漂浮型缓释片最优处方,采用湿法制粒压片制备胃漂浮型缓释片,对制备的胃漂浮型缓释片进行漂浮性与体外释放度测定。结果辛伐他汀胃漂浮型缓释片起漂时间小于1min,持续漂浮时间大于14h,在2,8和14h药物累积释放度分别达到8.66%,56.44%和95.17%,体外释药符合Higuchi方程。结论制备的辛伐他汀胃漂浮型缓释片漂浮性能良好,达到缓释药物的目的。     

氟啶酸眼用缓释凝胶的制备及释药研究

目的制备氟啶酸眼用缓释凝胶并研究其释放机理。方法建立UV测定制剂的含量及体外释药量,建立HPLC测定制剂离体角膜渗透量,采用溶出度法进行处方的体外释药试验,应用离体角膜进行体外渗透试验。结果亲水凝胶材料含量越小,氟啶酸从凝胶基质中释放越快,体外释药符合一级释放动力学方程;亲水凝胶含量高,体外释放符合H iguch i方程。结论氟啶酸眼用凝胶达到了缓慢释放的目的。     

甲磺酸二氢麦角碱缓释片的制备与体外释放特性研究

目的:制备甲磺酸二氢麦角碱缓释片,研究其体外释放特性。方法:以羟丙甲基纤维素(HPMC-K4M)为骨架材料,采用湿法制粒制备甲磺酸二氢麦角碱缓释片。以释放速率、累积释放度为指标,以载药材料(HPMC-K4M)、填充剂(乳糖、磷酸氢钙)和微环境p H调节剂(酒石酸)的用量为因素,采用单因素试验和正交试验对甲磺酸二氢麦角碱缓释片处方进行优化并验证;采用《中国药典》释放度测定方法比较进口和最优处方所制甲磺酸二氢麦角碱缓释片的体外释放特性。结果:最优处方为甲磺酸二氢麦角碱2.5 mg,HPMC-K4M 40 mg,乳糖70 mg,磷酸氢钙80 mg,酒石酸40 mg;所制甲磺酸二氢麦角碱缓释片可体外持续释药12h以上,12 h累积释放度为97.1%,与进口片剂比较累积释放度无明显变化,体外释药行为符合Higuchi方程。结论:成功制得具有缓释作用的甲磺酸二氢麦角碱缓释片。     

盐酸小檗碱控释片的制备

目的制备盐酸小檗碱控释片。方法以羟丙基甲基纤维素为辅料，制成控释片并进行体外累积释放度测定。结果体外释药基本达到零级释放过程，r＝0.997 4，体外释药量与释药时间具有良好的相关性。Peppas 方程中n值为0.896 6，控释片中药物的释放机制是骨架溶蚀。结论盐酸小檗碱控释片达到了设计要求，1 h内体外释药约为标示量的8%，12 h后释药约为标示量的75%。     

罗通定缓释片体外释放度的研究

目的建立罗通定缓释片体外释放度测定方法,评价其体外释药行为.方法用紫外分光光度法和体外释放度试验,考察罗通定缓释片在不同释放介质中和不同释放时间的累积释放度.结果罗通定在281 nm处有最大吸收,在5～250 μg/ml内与吸收度呈良好的线性关系:Y=0.0143X+0.0378, r=0.9999.罗通定缓释片在人工胃液中的体外释药行为理想,符合Higuchi方程:Mt/M∞=0.3933t1/2-0.2274, r=0.9992.结论本法简便、快速,适用于罗通定缓释片的质量控制.     

盐酸坦索罗辛缓释片的制备及其体外释药特性研究

目的:制备盐酸坦索罗辛缓释片,并考察其体外释药特性及机制。方法:以羟丙基甲基纤维素(HPMC)为骨架材料制备坦索罗辛缓释片;以累积释放度为指标,评价多种因素对体外释放速率的影响,并与普通片比较缓释性。结果:HPMC用量及制片压力对释药影响最大,二者最佳值分别为25%、8～11kg时缓释效果最佳,缓释片与普通片0.5h时体外累积释放度分别为10%、50%。结论:所制缓释片缓释效果优于普通片,其释药特性为药物扩散与溶蚀协同作用,释放机制为非Fick扩散。     

美乐托宁缓释片在不同介质中的释放试验

目的:制备美乐托宁缓释片,以国外上市制剂美乐托宁缓释片为参比制剂,考察自研制剂和参比制剂在不同pH释放介质中体外释放行为的相似性及体外释药机制。方法:采用释放度测定法转篮法的装置进行体外释放实验,用HPLC法测定释放度,采用f2相似因子对2种制剂释放曲线的相似度进行评价,并进行释放行为模型的拟合。结果:在不同pH的释放介质中,自制制剂释放度曲线与参比制剂比较,f2相似因子均大于50;美乐托宁缓释片在4种释放介质中体外释药拟合模型更接近一级方程、Higuchi方程和Peppas方程。结论:参比制剂与自制制剂在不同pH释放介质中的体外释放一致,释放机制为扩散释药。     

β-榄香烯聚氰基丙烯酸正丁酯纳米粒的体外释药特性研究

目的:研究β-榄香烯聚氰基丙烯酸正丁酯纳米粒(β-ELE-PBCA-NP)的体外释药特性。方法:采用透析袋扩散法考察其体外释药特性,释放介质为生理盐水(含50%乙醇、0.5%十二烷基硫酸钠);以高效液相色谱法测定其含量;比较β-榄香烯(β-ELE)溶液与β-ELE-PBCA-NP胶体溶液48h内的累积释放度,并考察β-ELE-PBCA-NP的释药机制。结果:β-ELE溶液8h的累积释放度已接近90%;β-ELE-PBCA-NP胶体溶液48h累积释放度为70.8%,且0.5h的累积释放度仅为8.7%,符合突释效应要求。体外释药模型以Weibull方程拟合程度最好(r=0.9977)。结论:与β-ELE溶液相比,β-ELE-PBCA-NP胶体溶液具有明显的缓释作用。     

非洛地平缓释片释放度比较

目的观察非洛地平缓释片体外释放度和治疗效果分析。方法照中国药典2000版二部和卫生部有关非洛地平质量控制标准的有关规定,采用转篮法,十六烷基三甲基溴化胺-磷酸盐缓冲液为介质,紫外分光光度法测定。结果非洛地平缓释片累积释放百分率符合H iguch i方程,释放速度符合零级模型。结论不同产品药物释放情况与临床治疗结论一致。     

Efficacy of gut lavage,hemodialysis, and hemoperfusion in the therapy of paraquat or diquat intoxication

Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents.Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1–2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1–2 ppm, the clearance values for hemoperfusion were some 5–7 times higher than those for hemodialysis.In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquat less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.

---

Zusammenfassung Klinische Untersuchungen und Laboratoriumsversuche wurden durchgeführt, um die Wirksamkeit von Darmspülung, Hämodialyse und Hämoperfusion bei Paraquat- und Deiquat-Vergiftungen zu prüfen.Bei einem Patienten wurde 30 Std nach Deiquat-Aufnahme durch Darmspülung 130mal mehr Deiquat entfernt als durch vollständige Aspiration des Mageninhaltes. In vitro-Versuche ergaben, daß bei Blutserumkonzentrationen von 1–2 ppm, die bei Vergiftungen oft gemessen werden, durch Hämodialyse keine toxikologisch relevanten Paraquat- oder Deiquat-Mengen entfernt werden können. Dagegen erwies sich die Hämodialyse bei 20 ppm und einer Blutumlaufgeschwindigkeit von 100 ml/min mit einer Clearance von 70 ml/min als wirksam. Die Hämoperfusion mit beschicheter Aktivkohle war in diesen Versuchen aber eindeutig überlegen, denn insbesondere bei Konzentrationen um 1–2 ppm waren die Clearance-Werte 5–7mal höher als bei der Hämodialyse.Die in vitro-Ergebnisse wurden bei einem Patienten mit einer Paraquat-Vergiftung bestätigt: Bei Konzentrationen unter 1 ppm war die Hämodialyse wirkungslos, während durch Hämoperfusion relativ hohe Clearance-Werte erreicht wurden, so daß der Serumspiegel rasch unter die Nachweisgrenze abfiel.

     

In vitro studies on sterically stabilized liposomes (SL) as enzyme carriers in organophosphorus (OP) antagonism

This study describes a new approach for organophosphorous (OP) antidotal treatment by encapsulating an OP hydrolyzing enzyme, OPA anhydrolase (OPAA), within sterically stabilized liposomes. The recombinant OPAA enzyme was derived from Alteromonas strain JD6. It has broad substrate specificity to a wide range of OP compounds: DFP and the nerve agents, soman and sarin. Liposomes encapsulating OPAA (SL)* were made by mechanical dispersion method. Hydrolysis of DFP by (SL)* was measured by following an increase of fluoride ion concentration using a fluoride ion selective electrode. OPAA entrapped in the carrier liposomes rapidly hydrolyze DFP, with the rate of DFP hydrolysis directly proportional to the amount of (SL)* added to the solution. Liposomal carriers containing no enzyme did not hydrolyze DFP. The reaction was linear and the rate of hydrolysis was first order in the substrate. This enzyme carrier system serves as a biodegradable protective environment for the recombinant OP-metabolizing enzyme, OPAA, resulting in prolongation of enzymatic concentration in the body. These studies suggest that the protection of OP intoxication can be strikingly enhanced by adding OPAA encapsulated within (SL)* to pralidoxime and atropine.     

Aquatic Insects and Trace Metals: Bioavailability,Bioaccumulation, and Toxicity

Abstract

The uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physico-chemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors.     

Pharmacological treatment of COVID-19: an opinion paper

The precocity and efficacy of the vaccines developed so far against COVID-19 has been the most significant and saving advance against the pandemic. The development of vaccines has not prevented, during the whole period of the pandemic, the constant search for therapeutic medicines, both among existing drugs with different indications and in the development of new drugs. The Scientific Committee of the COVID-19 of the Illustrious College of Physicians of Madrid wanted to offer an early, simplified and critical approach to these new drugs, to new developments in immunotherapy and to what has been learned from the immune response modulators already known and which have proven effective against the virus, in order to help understand the current situation.     

Alzheimer’s disease – current trends in basic and clinical research. Highlights from the 16th ECNP

Advances in the molecular biological knowledge of neuronal nicotinic acetylcholine receptors (nAChRs) have led to a growing interest by the pharmaceutical industry in the development of novel compounds that selectively modulate nAChR function. The ability of (-)-nicotine, an activator of nAChRs, to enhance attentional aspects of cognition in animals and humans, to exert neuroprotective and anxiolytic-like effects, and presumably to mediate the negative correlation between smoking and Alzheimer's (and Parkinson's) Disease, has focused interest on the potential therapeutic utility of modulators of nAChR function for treatment of some of the deficits associated with these progressive, neurodegenerative conditions. Numerous compounds are known which activate nAChRs and which might serve as lead compounds toward the development of such agents. The pharmacologic diversity of neuronal nAChR subtypes suggests the possibility of developing selective compounds which would have more favourable side-effect profiles than existing agents. This broader class of agents, collectively called cholinergic channel modulators (ChCMs), is anticipated to encompass compounds which would have more favourable side-effect profiles than existing agents, which generally exhibit low selectivity. This selectivity may be achieved by preferentially activating some subtypes of nAChRs (i.e., Cholinergic Channel Activators, ChCAs) or inhibiting the function of other subtypes (Cholinergic Channel Inhibitors, ChCIs). An overview of the biology of nAChRs and the rationale for the use of ChCMs for the treatment of dementia related to neurodegenerative diseases are presented, followed by a discussion of lead compounds and compounds under consideration for clinical evaluation.     

Steroidal sapogenin contents in some domestic plants

In order to find out the values of the steroid resources for the future use. the compositions and contents of steroidal sapogenins from 13 domestic plants have been investigated. As a result,Dioscorea nipponica, D. quinqueloba andSmilax china were found to have large amount of diosgenin. And pennogenin inTrillium kamtschaticum andParis verticillata, yuccagenin inAllium fistulosum, hecogenin inAgave americana and neochlorogenin inSolanum nigum were appeared to be major steroidal sapogenins.